Of known liquid foods obtained from oil seeds, soybean milk is the most common, the soybean being considered a kind of oil seed. There have been provided various proposals for the production of soybean milk from soybeans. However, soybean milk as produced by known methods is likely to become easily deteriorated in quality due to changes of surrounding conditions during storage, and such deterioration is accompanied by a disagreeable soybean odor, a roughness, a disagreeable bitterness, astringency, etc.
In addition, as soybean proteins are sensitive to heat and chemicals, the conventional techniques are often unable to cope with unexpected difficulties which often occur in the production of an acceptable and stable soybean milk.
Many proposals have been made to solve these problems so that improved soybean milk can be made which is consistently stable against changes in the surrounding conditions and without deterioration of quality even after longer than normal storage, but none of these proposals has been particularly successful.
It has previously been proposed by one of the present inventors to provide a method for the production of liquid food from oil seeds which method includes inactivating the enzymes in said oil seeds, noting Japanese examined patent publication No. 56-44701, but it has been found that the liquid foods obtained according to such method are not sufficiently stable when changes in surrounding conditions occur, and the liquid foods obtained easily deteriorate in quality under such conditions.